Urinalysis (cont.)

Siamak N. Nabili, MD, MPH

Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What are the pros and cons of dip sticks?

The main advantage of dipsticks is that they are convenient, easy to interpret, and cost-effective. They can be analyzed within minutes of urine collection in the doctor's office or in the emergency room to provide valuable information.

However, what can be learned from a dipstick is limited by the design of the dipstick. The main disadvantage is that the information may not be very accurate, as the test is time-sensitive. It also provides limited information about the urine, as it is qualitative test and not a quantitative test (for example, it does not give a precise measure of the quantity of abnormality). Therefore, normal and abnormal values are not reported as part of urinalysis results.

What is microscopic urinalysis?

The microscopic urinalysis is the study of the urine sample under a microscope. It requires only a relatively inexpensive light microscope. Cells and cellular debris, bacteria, and crystals in the urine can
be detected by this examination to provide further clinical clues.

How is microscopic urinalysis done?

Microscopic urinalysis is done simply pouring the urine sample into a test tube and centrifuging it (spinning it down in a machine) for a few minutes. The top liquid part (the supernatant) is discarded. The solid part left in the bottom of the test tube (the urine sediment) is mixed with the remaining drop of urine in the test tube and one drop is analyzed under a microscope.

The sediment is examined through the microscope under low-power to identify what are called casts, crystals, squamous (flat) cells, and other large objects.

Examination is then performed through the microscope at higher power to further identify any cells, bacteria and clumps of cells or debris called casts.